Zero-setting mechanism



Sept. 22, 1936.

l.. E. LEN-rz ZERO-SETTING MECHANISM Filed May 26, 1933 2 Sheets-Shes@ 1Figi.

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f 31a/vento@ -53 Lawrence Lent@4 L E. LENTZ 2,055,381

ZERO- SETTING MECHANISM Filed may 26, 193s 2 VSheets-Sheet 2 LawrenceELen.

Patented Sept. 22, 1936 UNITED STATES PATENT OFFICE ZERO-SETTINGMECHANISM Delaware Application May 26, 1933, Serial No. 672,961

19 Claims.

My invention relates to calculating mechanism, and more particularly toimprovements in Zero setting mechanism for registers.

The main object of my invention is to provide an eiiicient zero settingmechanism of relatively few parts and inexpensive construction adaptedfor incorporation in a register of the denominational, reversible Wheeltype.

Specifically, my invention seeks to provide simple and practical clutchdevices on the denorninational wheels of such a register, and on theshaft of said wheels, respectively, together with clutch control andshaft-rotating mechanism operative under control of a manual Zerosetting l5 lever, and by a sequence of quick operations, to

first clutch the wheels to the shaft, and subsequently to rotate theshaft to effect a Zero setting operation after rotation of the wheels ineither direction.

Other and subordinate objects will appear when the following descriptionand claims are read in the light of the accompanying drawings.

In the drawings:

Figure 1 is a view in side elevation, parts showing in section, of aregister equipped with a preferred embodiment of my invention, one sideplate of the register being removed to disclose the mechanism, the partsbeing shown in normal position.

Fig. 2 is a vertical section taken on the line 2--2 of Fig. 1 and drawnto an enlarged scale.

Fig. 3 is a detail View taken substantially on the line 3--3 of Fig. 2,illustrating one of a series of denominational Wheels of the register, ashaft upon which the series of Wheels are mounted, together withcooperating clutch devices on the Wheels and shaft, and a clutch controlblade member in the shaft, the parts being shown in normal clutchdisengaging position.

40 Fig. 4 is a detail view in side elevation, with parts showing insection, illustrating, in dotted lines, an initial stage in the Zerosetting operation and, in full lines, a final stage of the saidoperation.

Fig. 5 is a view similar to Fig. 3, with the parts shown in clutchengaging position.

Fig. 6 is a side elevation, partly in section, of the aforesaid shaft.

Fig. 7 is a side elevation of the blade member.

Fig. 8 is an end View of said member, and

Fig. 9 is a perspective View of a rocking element forming part of theclutch control mechanism.

The register shown in the drawings as embodying my invention, is what isknown as a column register for use with the well-known Elliott- Fisherwriting-computing machine of commerce, but it is to be understood thatthe invention is not restricted to use with this type of register alone,as will presently appear.

The register parts are enclosed in a casing I (Fig. l) formed by a base2, side walls 3, and a cover plate 4, provided in the upper frontportion thereof with the usual sight opening 5. Adjacent the sightopening 5 is a series of denominational 10 value-indicating wheels 6,bearing the usual symbols, 0 to 9, and freely rotatable on a shaft 'I.Subjacent the wheels 6 is a series of denominational, toothed numberwheels 8, designed to be selectively operated, clockwise for adding and15 counter-clockwise for subtracting, by the master wheel 9 of theElliott-Fisher machine, in a manner Well-known and requiring noexplanation. Value-indicating and number wheels, 6 and 8, ofcorresponding denomination are geared together 20 by means of gears IIIand II (see also Fig. 4) fast on said wheels, 6 and 8, respectively, andan intermediate idler gear I2. A centering and overthrow preventing rollI3 (Fig. 1) mounted upon an arm I4, tensioned by a spring I5, isprovided 25 for each number Wheel 8.

The register is equipped with transfer mechanism of the type featured inU. S. Patent No.

1,576,961, issued to Harry A. Foothorap, March 16, 1926, and includes aseries of transfer heads, 30 one of which is shown at I6, cooperatingwith the number wheels 8 and mounted on a shaft I'I to rock in oppositedirections, respectively, from a central normal position. Each transferhead I6 is provided with a trip finger I8 engaged by 35 a transfertooth, not shown, on a related number Wheel 8, whereby said heads aretripped from central position in one direction or the other, as the casemay be, when the value-indicating wheels 6 are rotated from 9 to 0registering position 40 or vice versa. Associated with each head I6 isactuating mechanism, including an actuator lever I9 pivoted at 29 to astationary mounting 2|, a. suitably connected motor spring 22 urgingsaid lever I 9 toward the axis of its head I6, and a link 45 23connecting each head I6 and its actuator lever I9 to form therewith, inthe normal position of the head I6, a toggle lock resisting the urge ofthe motor spring 22. Combined transfer pawls and check dogs 24,tensioned by suitably connect- 50 ed springs 25, are provided atopposite sides of the axis of the heads I6 to engage the number wheel ofnext higher order and execute a transferring operation thereon, as willbe clear. A detent 26, pivoted as at 2l, and tensioned by a 55 spring 28engages a roller 29 on each link 23 to yieldingly hold said link and theassociated head I6 in normal central position.

A zero setting, or clearing lever 30, and a toothed zero setting segment3| are mounted on` A transfer restoring bail 3:11, including a toothed'sector 38, is pivoted on a fixed shaftV 394 for movement against theaction of a suitably arranged spring 40, to engage the levers I9 andrestorey the transfer mechanism to normal position.Y

A rocking bail actuator 4I is pivoted at 42 and operatively connected at43 to said bail 3'7". A cam 44 on the Zero settingV lever 30 engagesaroller 45 onsaidactuator 4| to effect a transfer restoring operationupon movement in either direction, of the lever 30, and prior tomovement of the zero setting segment 3|. A toothed restoring slide 46 isgeared to the toothed sector 38 by a pinion 41, and projects through thefront wall of the casing I for operation bythe carriage oftheElliott-Fisher machine in a manner well-understood in the-art..

The above-described cooperative arrangement of'aV Zero setting lever,zero setting segment and transfer restoring mechanism is featured intheco-pending application of Harry A; Foothorap, Serial' No.. 505,905,filed December 31, 1930, and no claim is'made theretov herein, exceptinsofar as theA zero setting lever and segment enter into combinationwith other elements as hereinafter defined.

Coming nowrto the speci'c features of my invention, azero setting shaft4B, (Figs. 1, 2 and 4) for the number wheels 8, is journaled at one endin one side wall 3 of the casing I, the other end having Afast thereon atoothed pinion 49 meshing withthe Zero-setting; segment 3| and providedwith a hub 50 journaled in the other side wall 3 of said casing. Clutchmechanism is provided between the shaft 48 and number wheels 8,respectively, the clutch device on the shaft taking` the formof alongitudinally extending substantially radial slot in said shaft,providing a clutch shoulder 52, (Figs. 3 andv 5) and terminating at theends of the shaft in deep kerfs 53 extending diametrically through theshaft (Figs. 2 and 6), for'a.` purpose'presently seen. The clutch deviceon each of the totalizer wheels 8, includes a clutch dog 54 pivotedintermediate its ends to thev web of its wheel and is backed by spring55, the

springs tending to urgethe toothed ends of saidV dogs into the slot 5|',a-nd against said shoulder 52, and'a clutch control blade member 56accommodated in and bodily movable radially of said slot in oppositedirections to open and close the latter, respectively, andthereby'enable 'engagement and effect disengagement of the clutchdevices. Blade member 56` is provided with laterally extending guides 5lseated in the kerfs 53 to limit endwise movement of the blade and toguide the blade in its radial movement, as well as to Aprevent cooking.or skewing of the bladeY during suchmovement. Springs 58 (Fig. 2) arearranged V mico-acting, registering pockets 59 and 6D formed Y inthe-blade member 56 and the shaft 48, respectively, to normally' urgesaidv member in one' direction, i. e1., radially inwardly of the shaftV48 to free the slot 5| and thus enable engagement of the clutch devices.

A rocking blade controlling element 6|, (Figs. 9, 1, 2 and 4) includinga pair of spaced apart levers 62, is pivoted at 63 to engage said leverswith the lateral guides 51 of the blade member 56 to move the latter inthe opposite direction, i. e., outwardly of the shaft 48 and therebyclose the slot 5 I and effect disengagementof the clutch devices. Topermit proper engagement of one lever 62 with its related guide 51, thehub of the gear 49 is slotted as at 63 (Fig. 4). A spring 64 having vitso-pposite ends connected to the element 6| at 65 and to a fixed stud 66,urges said elementtoward an ineffective position against a stop 6?.Radial. movement outwardly of the clutch control blade member 56 tocause the member to disengage the toothed ends of the dogs 54 fromengagement with the side wall 52 of the slot 5|', and'to close the slot5|, is effected by operation of theV zero setting lever 36, the cam 4'4of which is adapted toV operate upon an ex'- tension 68 on the element6I,. as follows:

In'` the normal position of the'- parts, that is to say, the Zeroregistering position of. the wheels 6, asY shown .in Figs. l and 2, theshaftV 48 is so located relatively to the number wheelsx that the slot5I is in position to enable the toothed ends ofthe dogs 54 to enter thevsame. 'The cam44, however, mantains the blade-controlling element 6| inits effective position in which the levers 62 engage the ends of thelateral guides 5'Irof the bladev member 56 to project the latteroutwardly against the` tension of its springs 58 so that the outerrounded; edge of the blade 56- constitutes` a continuation of thevperiphery of the shaft 48,V

in the before-described clutch-disengaging position,andthe Wheels 8arefree-to rotate in either direction on said shaft. In this positionofthe parts, the free ends of the levers 62 one of which passes throughther slot 63@L in the hub of the gear 49, engage the walls of the kerfs53 in the ends of the shaft to lock the shaft 48 in normal position.Upon initial-forward movement of the zero settingv lever 36, and priorto operation of the Zero setting segment 3|, asshownrindotted lines inFig. 4, thev cam 44 disengages the extension 68 and frees theblade-controlling element 6| for movement to ineffective position by itsspringv 65, whereupon the blade member 5.6 is bottomed in the slot 5I ofthe shaft 56 by its springs 58 to enable the before-described clutchingaction (Fig. 4). Continued advance of the zero setting` lever 30 nextoperates the segment 3| downwardly to impart a complete rotation to theYshaft 48 and set any wheel 6, registering other than Zero, back to Zeroregistering position, as shown inv full lines in Fig. 4'. Retraction ofthe zero setting lever 36 rotates the shaft 48 reversely and idly aswill be clear and at the end of this operation, the cam 44 returns theblade-controlling element 6|v to eiTective position to move the blademember 56-to cutch-disengaging position (Fig. 3) and to lock the shaft48 against rotation.

The lateral guides5l at the opposite ends of the clutch control blade 56vary in length, for mechanical reasons, the right hand guide (Fig. 7)being longer than the left hand guide, and. it may be of slightlylessbreadth, as shown.

As a result, the arms 62 of the blade-controlling elements 6| are not indirect horizontal alignment, thefleft hand arm 62 (Fig. 2), which is theright hand arm in Fig. 9, being positioned following disclosure.

It must be borne in mind that this invention has been particularlydesigned for use with an adding and subtracting totalizer, wherein thetotalizer wheels 8 rotate in one direction or the other depending uponwhether the amount is added to or subtracted from the amount already onthe totalizer, though not restricted in its use thereto.

Therefore, the wheels may turn past the zero point in either directiondepending upon whether the amount registered on the totalizer ispositive or negative in character.

Since the arms 62 normally lock the totalizer shaft 8 in a predeterminedposition, where it is held throughout a calculation, the slot 5| must benormally closed to prevent the entry of the toothed ends of the dogs 54as the wheels 8 pass to either side of Zero.

For this reason means is provided in the form of the arms 52 and cam 44which not only locks the shaft 48 against rotation, but more importantstill, locks the clutch-control member or blade 55 in its outermostposition so that its rounded outer edge completes the peripheral surfaceof the shaft 48 and masks the shoulder 52 to eliminate any contact ofthe dogs 54 therewith.

The outer edge of the clutch-control blade 56 at its ends, strikesagainst the left hand side frame 3 (Fig. 2) and against the innerperiphery of the hub 58 of the pinion 49 to arrest the blade with itsouter edge in proper position.

The operating segment 3| is in constant mesh with the pinion 49 of thetotalizer supporting and clearing shaft 48, the relation being such thatWhen the operating segment is in its normal position at o-ne end of itstravel, (the upper end, in the embodiment shown in Fig. 1), the openside of the slot 5| is uppermost', and when the dogs 54 are then alinedwith the slot, the zeros on the wheels 8 are at the sight opening 5. p

Addition and subtraction of amounts on the totalizer turns the wheels 8on the shaft 48 so that the toothed ends of the dogs may lie at any often positions circumferentially of the shaft.

In resetting the wheels to zero, the operator swings the actuator orhandle 30 from the position shown in Fig. 1 to that shown in full linesin Fig. 2.

The rst step of travel of the actuator 30 in counter-clockwise directionto the dotted line position shown in Fig. 4, has no effect upon theactuator segment 3|, due to the lost motion connection 33, 34, but doesshift the cam 44 on the operator lever 30 to withdraw the high point ofthe cam from contact with the finger 58 of the blade-controlling bail6|, 62, to free the latter to the action of its spring 64.

The spring thereupon rocks the bail 6|, 62, counter-clockwise,withdrawing the free ends of the suppo-rting arms 62 from the lower endsof the lateral extensions 51 on the clutch-control blade 55, whereuponthe springs 58 force the blade radially inwardly until it seats on thebottom of the slot 5| in the shaft 48.

The springs 58 assist the spring 64 in rocking the supporting armsdownwardly, and cause the masking or clutch-control blade to followuntil arrested by its seat in the bottom of the slot 5|, thus avoidingloss of time in withdrawing the filler from the open side of the slot,and in unmasking the shoulder 52 of the shaft 48.

Immediately thereafter, the stud 33 on the operating lever 3U contactsthe left hand end of the slot 34 (Fig. 1) and rocks the actuator segment3| counter-clockwise, the segment, of course, turning the clearingpinion 49 and clearing shaft 48 in clockwise direction, through acomplete rotation.

'Ihe open-sided slot 5| of the shaft thus makes a complete orbit and itsshoulder 52 serves on this counter-clockwise stroke, as a hunting clutchmember to collect and gather together all the clutch dogs 54 and theirwheels, in whatever positions the latter may be.

In so doing, the slot 5| is presented to the dogs 54, the teeth of whichsuccessively snap into the slot under the tensions of their springs 55,whereupon the shaft 48 turns the wheels clockwise as in adding amounts.

At the end of the counter-clo-ckwise stroke of the operating lever 30,the wheels 8 all stand at Zero, the actuating segment 3| is at itslowermost limit of travel, and the operating lever is in a substantiallyvertical position, as shown in Fig. 4.

The operating lever 3|! is now restored im clockwise direction to itsnormal position, together with the actuating segment 3|, which latterimparts a complete rotation in the reverse (counter-clockwise) directionto the clearing pinion 49 and slotted clearing shaft 48, to return themto their normal positions.

The slo-t in the shaft, during such counterclockwise rotation, merelylifts the clutch dogs 54 as the slot escapes therefrom, due to theinclination of the teeth of the dogs, as shown at '|'5 in Figs. 3 and 5,the spring-pressed detents I4 (Fig. 1) serving to retain the wheels 8 intheir adjusted zero positions, during such reverse rotatio-n of theshaft.

As the actuating segment 3| reaches its home position, its arm 35contacts the hub 35 and arrests the segment.

Meanwhile, just prior to the arrival of the operating lever 3G in itsnormal position, the cam 44 on the operating lever Wipes over the finger88 of the blade-controlling bail 6|, 62 to raise the arms 62 so thattheir free ends enter the wide kerfs 53 at the ends of slot 5| andcontact the lower ends of the depending extensions 51 of theclutch-control blade 56 to shift the latter radially outwardly of itsslot 5|, so that its oonvex outer edge will lill up or close the slotand complete the periphery of the shaft 48.

The kerfs 53 in the shaft 5|, and the slot 63 in the hub of the pinion49, are of sufficient width to accommodate the ends of theblade-controlling arms 62, as the shaft 48 nears its home position.

The rotation of the numeral wheels 8 from their 9 to their 0 positionsjust as the operating lever 30 is reaching the end of itscounterclockwise stroke, trips all the carrying mechanisms I8, I8, butno carrying action can occur at this time, because, during the travel ofthe operating lever 38 in counter-clockwise direction, the cam 44operates upon the bail actuator 4| to rock the latter counter-clockwise.The bail actuator 4|, by its slot and pin connection 43 with thecarry-restoring bail 3l, rocks the restoring bail clockwise, so that bythe time the carrying mechanisms are tripped, the restoring bail liesadjacent the free angularly disposed ends of the bell crank arms |9 andoperates to at once restore the tripped carrying mechanisms before theyhave advanced su'iciently to effect a carry.

The operating lever 30, on its return to normal, withdraws the cam 44 toenable the spring 4l). to return the carry-restoring bail 31 and thethereto-connected bail actuatorlll to their home positions.

It will. be evident that the springs 58, in combination with the arms 62constitute one form of means to shift the clutch-control blade inwardlyand outwardly in the slot.`

The foregoing constitutes a detailed description of a preferredembodiment of my invention, but it is to be understood that right isherein reserved to such modifications in structure as fall fairly withinthe sco-pe of the protection prayed.

What I claim is:

1. In a register, the combination with a rotatable shaft having alongitudinally-extending slot formed therein; andV a series ofdenominational wheels journaled on the shaft; of Zero setting means forthe wheels, including a dog mounted on each wheel, and having a toothnormally tending to be engaged by a Wall of the slot; means to rotatethe shaft to cause that wall of the slot to engage the dogs and returnthe wheels to zero; a filler member seated in the slot; and means toshift the ller member to cause its outer edge to completely iill theslot, and to position it to leave the outer side of the slot open.

2. In a zero setting mechanism for registers, the combination with arotatable shaft having a longitudinally-extending slot formed therein;and a series of denominational wheels journaled on the shaft; of a dogon each wheel, having a tooth to be engaged by a wall of the slot;operating means to turn the shaft to cause that wall of the slot toengage the dogsY and return the wheels to Zero; a ller member shiftablymounted in the slot; and means to shift the ller member to cause itsouter edge to complete the periphery of the shaft at points in theplanes of the teeth of the dogs, and to depress the filler member intothe slot to open the latter for engagement with the dogs.

3. In a zero setting mechanism, the combination with Xed supports; arotatable shaft journaled in the supports, and having a longitudinallyextending slot formed therein; and a series of denominational wheelsjournaled on the shaft; of a clutch dog on each wheel, having a tooth tobe engaged by a wall of the slot; operating means to rotate the shaft tocause that wall of the slot to engage the clutch dogs and return thewheels to zero; a clutch-control member shiftably mounted in the slot;and means to shift the clutch-control member to cause it to block theinter-engagement of said wall of the slot and the dogs, and to displacethe clutch-control member to enable contact of the wall of the slot withthe dogs.

4. In a zero setting mechanism, the combination with a rotatable shaft;means to rotate the shaft; a series of denominational wheels journaledon the shaft; and clutch members on the respective wheels, with whichthe shaft coacts to restore the wheels to zero; of means movablerelatively to, and under control of, the shaft-rotating means to lockthe shaft against, and to release it for rotation; and means on theshaft controlled by the said shaft lockingY and releasing means, toenable and to prevent co-action between the clutch members and theshaft.

5. In a Zero setting mechanism, the combination with a rotatable,slotted shaft; means to rotate the shaft; a series of denominationalwheels journaled on the shaft; and clutch members on the respectivewheels, with which one wall of the slot coacts to restore the wheels tozero; of a longitudinally-extending blade seated in and radially movableofv the shaft, to control the clutching action between the wall of theslot and the wheels; and means, under control of the shaft-rotatingmeans, to shift the blade to its effective and ineffective positions,respectively.

6. In a zero setting mechanism,.the combination with a rotatable,shouldered shaft; means toV a series of denominational to prevent,co-action between the co-acting clutch members, respectively.

'7. In a Zero setting mechanism, the combination with a rotatable shaftequipped with a clutch member; a series of denominational wheelsjournaled on the shaft; clutch members on the respective wheels to coactwith the clutch member on the shaft; and means to rotate the shaft tocause its clutch member to engage the clutch members on the wheels andreturn the wheels to zero; of means normally masking the clutch memberVon the shaft; and means to shift the masking means to enable and toprevent co-action between the co-acting clutch members, respectively.

8. In a zero setting mechanism, the combination with a rotatable shaftequipped withfa clutch member; a series of denominational wheelsjournaled on the shaft; clutch members on the respective wheels to coactwith the clutch member on the shaft; and means to rotate the shaft tocause its clutch member to engage the clutch members on the wheels andreturn the wheels to zero; of means normally masking the clutch memberon the shaft; and means under control of the shaft-rotating means toshift Vthe Vmasking means to effective and ineffective positions.

9` In a zero setting mechanism, the combination with a rotatable shaftequipped with aA clutch members on the wheels and return the wheels.

to Zero; of means normally masking the clutch member on the shaft; andmeans to shift the masking means to masking and unmasking positions andto concomitantlylock the shaft against,A

and release the shaft for rotation, respectively.

10. In a zero setting mechanism, the combination with denominationalwheels; a rotatable shaft; and co-acting clutch devices on the wheelsand shaft, respectively; of a clutch-control means shiftable to maskingand unmasking positions relatively to oneof the clutch devices, andtensioned to assume its unrnasking position; means to rotate the shaft;and means under control of the shaft-rotating means to normally hold theclutchoontrol means in its masking position.

11. In a zero setting mechanism, the combination with denominationalwheels; a rotatable shaft; and co-acting clutch devices on the wheelsand shaft, respectively; of a clutch-control means shiftable to maskingand unmasking positions relatively to one of the clutch devices, andtensioned to assume its unmasking position; means to rotate the shaft,including relatively movable actuating and operating members; a camoperable by the operating member; and means operable by the cam, tonormally hold the clutch-control means in its masking position.

12. In a zero setting mechanism, the combination with a rotatable,slotte-d shaft; means to rotate the shaft; a series of denominationalWheels journaled on the shaft; and clutch members on the respectivewheels, with which one wall of the slot co-acts during rotation in onedirection to restore the wheels to zero; of a longitudinallyextendingblade seated in and radially movable of the shaft, to control theclutching action between the wall of the slot and the wheels; and meansto shift the blade to enable and to prevent the clutching action,respectively.

13. In a zero setting mechanism, the combination with denominationalwheels; of a rotatable, slotted shaft; clutch ldogs on the Wheelsadapted to engage the slot to enable the shaft to return the wheels tozero; a masking member shiftably mounted in the slot in the shaft toopen and close the slot; shaft-rotating means; and means to shift themasking member to enable, and to prevent engagement of the clutch dogsand shaft, respectively.

14. In a zero setting mechanism, the combination with a rotatable,slotted shaft; means to rotate the shaft; a series of denominationalwheels journaled on the shaft; an-d clutch members on the wheels adaptedto be engaged by one wall of the slot, to return the wheels to zer-o; ofa clutch-control member seated in, and adapted for movement radially of,the slot to mask and unmask the slot; an-d means operable relatively tothe clutch-control member to shift the latter to mask the slot, anddisengage the clutch members therefrom, the last-named means effectivein one of its positions, to lock the shaft against rotation.

15. In a zero setting mechanism, the combination with a rotatable,slotted shaft; means to rotate the shaft; a series of denominationalwheels journaled on the shaft; and clutch members on the wheels adaptedto be engaged by one wall of the slot in the shaft, constituting aco-acting clutch member, to return the wheels to zero; of aclutch-control member seated in, and adapted for m'ovement radially of,the slot, to mask the slot, and positively disengage the clutch members,and to unmask the slot to enable co-action of the clutch members.

16. In a Zero-resetting mechanism for registers, the combination with arotatable, slotted zeroresetting shaft; a plurality -of denominationalWheels journaled thereon; a zero-resetting dog mounted on each wheel,and having a tooth normally ten-ding to engage either wall of the slot,depending upon the direction of rotation of the wheel; and means to turnthe shaft to cause one wall of the slot to engage the dogs and returnthe wheels to zero; of means adjustably accommodated in the slot, whichmeans, in one of its positions lies below the outer end of the slot toenable one wall to engage the dogs, and to close the slot against theentry of the dogs, when in another position; means to normally retainthe adjustable means in position to close the slot; and means to releasethe retaining means, to enable the adjustable means to move to itsfirst-named position.

17. In a Zero setting mechanism, the combination with a slotted shaft; anumeral wheel journaled on the shaft; and a clutch member on the wheelto engage the slot in the shaft; means to rotate the shaft in onedirection to cause its slot to engage the clutch member on the wheel,and return the wheel to zero, and then reversely rotate the shaft to itsinitial position; of means to normally mask the slot; and means to shiftthe masking means alternately from and to its masking position in timedrelation with the beginning and termination of the rotation of theshaft, to enable co-action between the slot and the clutch member, andto disengage the clutch member from the slot and mask the latter.

18. In a Zero-resetting mechanism, the combinati-on with a rotatable,slotted shaft; and means to rotate the shaft; of a series of-denominational wheels journaled on the shaftv for rotation in eitherdirection; engaging members on the respective wheels, in contact withthe shaft, and engageable thereby to restore the wheels to zero as theshaft is rotated; a control member in addition to the engaging members,having at least two positions, in one of which it enables engagement ofthe engaging members and the shaft, and in the other of which itpositively controls the engaging members to prevent engagement thereofand the shaft; and means to shift the control member to either of sai-dpositions.

19. In a zero-resetting mechanism, the combination of a rotatable,shouldered shaft; means to rotate the shaft; a series of denominationalwheels journaled on the shaft for rotation in either direction; clutchmembers shiftably mounted on the wheels, and in contact with the shaftthe shoulder on the shaft constituting a clutch member to co-act withthe clutch members on the wheels to return the wheels to Zero; and aclutch-control member, in addition to the coacting clutch members,seated in, and radially shiftable relatively to the shaft, and clutchmembers to control co-action between the co-acting clutch members; andmeans to shift the clutchcontrol member to enable and to preventcoaction between the co-acting clutch members, respectively.

LAWRENCE E. LENTZ.

